Haiti Won't Be Able to Handle Ivan ...

[Swimdude]

I still say Ivan doesn't make it to a cat. 5. Has anyone stopped to think about how incredibly RARE that it?

[donsutherland1]

Swimdude,

The landfall of Category 5 storms is exceptionally rare (2/31 major hurricanes that made landfall since 1950 were Category 5 storms). The formation of Category 5 storms is infrequent though not rare:

Since 1950 (the figures include Charley and Frances):

Category 4 Storms: 49
Category 5 Storms: 22

Thus, 31% of storms that reached Category 4 status ultimately have gone on to become Category 5 hurricanes. However, somewhat fewer than 1 of 15 hurricanes that have formed have become Category 5 storms.

Since 1950, 20 years have seen one or more Category 5 hurricanes develop:

1950
1951
1955
1957
1958
1960**
1961**
1964
1965
1967
1969*
1971
1977
1979
1980
1988
1989
1992*
1998
2003

*-denotes Category 5 hurricane with a U.S. landfall

**-denotes two Category 5 hurricanes

[donsutherland1]

Hurricane Ivan became yet another storm that reached Category 4 status after experiencing a 10 mb drop in pressure from below 970 mb over a short period of time.

Ivan became the season's fourth major hurricane and third Category 4 storm. The last time a season had more than 3 Category 4 or stronger storms was 1999. Then, the hurricane season saw 5 Category 4 hurricanes.